Adam Clark, 32 cleans a filthy chain on an old bike that a customer uses all year round. Clark has a mobile bike repair business that he started about three years ago and he covers Chicago from around 5500 south to the Evanston border. Photographed Thursday, March 29, 2012.

Adam Clark, 32 cleans a filthy chain on an old bike that a customer uses all year round. Clark has a mobile bike repair business that he started about three years ago and he covers Chicago from around 5500 south to the Evanston border. Photographed Thursday, March 29, 2012. (Nancy Stone, Chicago Tribune)

Like new cars, new bicycles depreciate dramatically the moment they leave the cycle shop. So buying used can be a better value for your money, especially if you can score a decent ride for less than $100.

The problem is refurbishing an older bike to a safe and comfortable riding condition. Fortunately, many bike repairs and upgrades are relatively simple and cheap.

Even if you use a cycle shop to complete the repairs, you might be able to make a $75 used bike road-ready for an additional $50 to $75, said Andrew Bernstein, gear editor at Bicycling magazine. Of course, it depends on what the bike needs.

"A bike depreciates at least 50 percent when you walk out the shop door, so you can get a very good deal on a used bike, especially if you're just going to be riding around town and don't need a high-performance machine," he said. "There are lots of great used bikes out there. For many people it's a great alternative to getting a new bike because sometimes you can get a nicer bike than you could afford new."

Prices of used bikes sold at yard sales can vary widely and aren't always logical. That's because people selling the bikes sometimes are unfamiliar with how valuable it is.

"You could see a $2,000 bike that looks dirty and grubby and pick it up for $50," said Alex Ramon, who worked in bike shops for 10 years and created BicycleTutor.com, which offers written and video lessons on common bike repairs and maintenance. "Nobody ever needs a new bike, in my opinion. Even the worst bike, as long as you love it, can be refurbished and brought back to life."

Jeff Yeager, who has bicycled more than 100,000 miles and is author of frugality books, including "The Cheapskate Next Door," said he regularly shops thrift stores and yard sales for parts for his 30-year-old bike.

"I think it's fair to say that if you shop carefully, you can find a decent bike at a thrift store or yard sale for under $50, which you can make roadworthy for about the same amount, assuming it just needs simple repairs you can do yourself," Yeager said.

"Bicycles, like so much exercise and recreational equipment, is an impulse buy for many people, who then immediately lose interest in it. So it ends up in the garage, and then the garage sale, with little if any damage or wear and tear. It's outdated but still perfectly functional with minor repairs."

Here are a few basic tips for refurbishing an older bicycle.

Safety first. "The first thing you want to check is anything that is responsible for supporting the rider," Bernstein said. For example, make sure the handlebar is secure.

"If it's not, it could be something as simple as tightening a bolt," he said.

Check the saddle and make sure the brakes work. And if you'll ride in the evening or early morning, install lights. A helmet is a necessity and not something to buy used because the foam padding breaks down and becomes less effective after about three years, Bernstein said.

Brakes. "Any bike that's been sitting a long time and hasn't been used much is likely to need new brake pads," Bernstein said. The parts might cost $7 or $8, plus $20 to have them installed, he said.

"It's not a hard job, but I wouldn't suggest somebody who knows nothing about bikes do it on their own," he said.

Tires. "Dry rot is common in tires and tubes that have been sitting uninflated for a period of time," Yeager said. "So they often need to be replaced, rather than just inflated and patched. The good news is, new tires and tubes are usually pretty cheap and easy to install."

Yeager recently found a 1970s-era 10-speed Raleigh bike for $20 at a thrift store.

"I could tell it had probably been ridden only a few times in its history. Even though it had a little rust on it, it had no measurable wear and tear." He spent about $40 on new tires and tubes, made some adjustments and it was "good as new." He figures a comparable bike today would cost more than $600.

Chain. The best thing you can do for many older bikes, especially if they squeak when ridden, is to lubricate the chain, ideally using chain lubricant, which costs about $10, Ramon said. Yeager agrees.

"Most used bikes are desperately in need of proper lubrication — think Tin Man in 'The Wizard of Oz' — and some adjustments to the gears, cables and brakes," Yeager said. "But that's not typically complicated or costly."

Cables. Brake cables and shift cables are also pretty cheap. Over time, cables stretch and should be replaced occasionally as a maintenance item anyway, Ramon said. You can replace them yourself, but you'll definitely need instructions, he said.

Gear shifting. There could be many reasons why gears don't shift properly, but often it's a need for a simple adjustments of the derailleur, Ramon said. Again, you'll need good instructions. Bernstein agrees. "It's not a difficult job, but for someone who's never done it before it's easy to do wrong," he said.

How-to advice. Fortunately, you have good resources for do-it-yourself repairs. One is Bicycling magazine's website, which has articles and videos on maintenance and repair at bicycling.com/maintenance. It also has a book by Todd Downs, "The Bicycling Guide to Complete Bicycle Maintenance and Repair." You can find online articles and YouTube videos, but results will vary widely in quality. Ramon's site, bicycletutor.com, costs $5.95 for a month of access to more than 50 professional-quality videos. The fee helps him defray website costs, he said.

Yeager suggests joining a local bike club, many of which offer repair classes. "And there are always lots of self-appointed mechanics in the group who thrive on fixing other people's problems," he said.

Tools. Some repair jobs require tools you might not have. You can get a very limited bicycle tool kit for about $20 or a more extensive one for home use for $75 to $100. Ramon recommends the Park brand of tools and at least getting a set of metric open-end wrenches, a set of metric Allen keys and a tire lever for fixing flats. Of course, buying tools adds to the cost of refurbishing the bike. If you won't use tools often, it might be better to let a pro complete the repairs.

If you haven't purchased a used bike, maybe at a garage sale or from a classified ad on Craigslist.com, do some homework ahead of time and inspect the bicycle carefully.

Lots of rust is a bad sign, possibly indicating it's been left in the rain, which can lead to a host of problems, Ramon said. Try to raise and lower the seat. Sometimes the seat gets stuck and becomes unadjustable.

Frame problems are bad news, Yeager said. "Don't buy a bike with a bent frame or any clear signs of frame damage," he said. "It probably can't be repaired and will lead to further problems down the road."

Similarly, wheels that don't spin properly could be a problem. It could mean a simple, inexpensive fix such as repairing a few broken spokes, or it could need a new wheel, which can be pricey or hard to find for older bikes. "Unless you know what you're looking for, it's probably best to stay away from used bikes that have wheels that are seriously out of balance," Yeager said.

If you're unfamiliar with bikes, take along a knowledgeable friend.

"Consider the simplest bike that will meet your needs. Having 15 or 20 gears or 'speeds' really isn't necessary for most cyclists. It's just more stuff that can break and cause problems," Yeager said.